Axillary dissection in breast cancer is performed to stage the tumor and to obtain regional tumour control. It is associated with some morbidity. Recently mention was made of post-axillary dissection pain of the arm following damage to one or more of the intercostobrachial nerves. In the University Hospital of Utrecht a radical axillary dissection is routinely performed for breast cancer with transection of the sensory intercostobrachial nerve(s). To evaluate the inherent morbidity of this operation, we interviewed and examined 71 women (75 axillae) who had undergone an axillary dissection for carcinoma of the breast between January 1987 and January 1990. In almost all cases a sensory deficit was present in the axilla and/or arm. In 23 patients (26 sides; 35%) there was pain in the arm, always in the innervation area of the intercostobrachial nerves. One-third of these cases had a NRS score of 5 or higher, indicating moderate to severe pain. Seroma and lymphedema were found in 21 patients. In 6 shoulders abduction was reduced to 90 degrees. The several complaints were non-invalidating to 48 patients, slightly invalidating to 13 and moderately invalidating to 10 patients. At present, histological examination of the axillary nodes is still the best way to detect metastases, and it has implications for adjuvant therapies. The results of this study indicate that routinely sacrificing the intercostobrachial nerves during axillary dissection may result in annoying sensory changes and that efforts should be made to preserve one or two of these nerves during the operation.